Hydraulically actuated attachment for power-driven tool chucks



Oct 1957 c. L. GRAYBILL HYDRAULICALLY ACTUATED ATTACHMENT FOR POWER-DRIVEN TOOL CHUCKS Filed March 4, 1955 4 CAIN Ta/v l... ERA YE/LL.

IN V EN TOR.

Arr Y HYDRAULICALLY ACTUATED ATTACHMENT FOR POWER-DRIVEN TOOL CHUCKS Clinton L. Graybill, Superior, Mont.

Application March 4, 1955, Serial No. 492,162

3 Claims. (Cl. 192-30.5)

This invention relates to an hydraulically driven attachment for power driven tool chucks.

One of the principal objects of the invention is to provide an attachment of this character which is of simple, efficient, durable and lightweight construction comprising a minimum number of parts and wherein clutch elements are automatically united and driven by fluid pressure.

Another object is to provide an attachment of this character which will operate with maximum eficiency and smoothness at all times regardless of the operating temperature of the hydraulic fluid.

A still further object is the provision of clutch members in the form of cooperating ratchet teeth which are of such angular profile as to insure smooth and progressive positive driving engagement with each other.

The foregoing and other objects will appear as my invention is more fully hereinafter described in the following specification, illustrated in the accompanying drawings, and finally pointed out in the appended claims.

In the accompanying drawing:

Figure 1 is a longitudinal sectional side view of the invention.

Figure 2 is a view of the left-hand end of Figure 1 with a closure plug removed.

Figure 3 is a view similar to Figure 2 with the closure plug and a fluid distributing disc removed.

Figure 4 is a sectional end view taken approximately along the line 4-4 of Figure 1.

Figure 5 is a view of one end of a piston and Figure 6 a view of the opposite end thereof.

Figure 7 is a longitudinal sectional side view of a modified form of the invention.

Figure 8 is a composite side view of the piston and a tool chuck.

Figure 9 is a side view of the piston provided with a spring-urged check valve.

Referring now more particularly to the drawing:

Reference numeral 1 indicates a main housing of hollow cylindrical form for the major portion of its length and internally threaded at both ends as at 2 and 3 to receive externally threaded plugs 4 and 5, respectively.

One end of the housing is closed as at 6 and eccentn'cally bored as at 7 to provide a housing for a vane pump 8 provided with radially movable vanes 9 at all times in rotating contact with the wall of the eccentric 'bore 7. The plug 4 is formed with an extension 10 for engagement with the chuck of any type of power driver (not shown) whereby the housing 1 will primarily rotate with respect to the vane pump 8. The portion 6 of the (housing 1 is formed with an inwardly extending portion 11 flattened on opposite sides as at 12 and at all times slidably engaged with a bifurcated extension 13 of a piston 14. The opposite face of the piston is formed with radially disposed ratchet teeth 15 for cooperation with companion ratchet teeth 16 formed on the inner face of v a tool chuck 17 formed with a tubular extension 18 constituting the chuck proper and rotatably extending out- Wardly through the plug 5. The inner end of the chuck atent 17 is centrally bored and internally threaded as at 19 for threaded engagement with the externally threaded end of a hollow shaft 20 upon which the piston 14 is slidably and rotatably mounted. The opposite end of the hollow shaft is formed integral with the vane pump 8. The central bore in the chuck is in communication with the interior of the main housing 1 by a port 22 and also with the interior of the hollow shaft. An opening 23 extends through the piston 14 and is regulatable by any approved type of needle valve 24. The inner end of the pump housing 7 is in communication with the space between the piston 14 and the closure 6 by openings 25.

The outer end of the pump housing 7 is closed by a disc 26 secured in place by the plug 4 and formed with two openings 27 and 28. The outer face of the disc is recessed as at 29 to provide space for the passage of fluid from the hollow shaft 20 in through the opening 27 and out through the opening 28 into the pump housing from where it is forced through the apertures 25 against the piston 14, through the restricted opening 23 and under suction through the duct 22 and back into the hollow shaft 20.

The operation of the invention is as follows:

With the parts in the positions shown in Figure 1 and assuming that a driver bit in the chuck 18 is engaged with a wood screw to be driven into a workpiece with which it has made its initial starting contact and whereafter the torsional resistance of the screw will gradually increase until the screw is finally driven home. Then when the main housing 1, which is filled with fluid, is put into rotation by the power driver, the fluid Will be forced by means of the now stationary vanes 9 of the pump through the apertures 25 and against the piston 14 which is, of course, rotating with the housing. The fluid under pressure from the pump will force the piston toward the tool chuck to operatively engage their respective ratchet teeth 15 and 16 to drive the tool chuck, driver bit and the screw. When the resistance of the screw becomes greater than the force holding the ratchet teeth in engagement with each other, the teeth 15 and 16 will cam out of engagement with each other and the resultant momentary release of the piston and hence the housing 1 will reactivate the pump to instantly replenish the volume of fluid necessary to reengage both sets of teeth. This repeated disengagement and reengagement of the teeth sets up rotating impacting forces. It will be observed that the combined area of the apertures 25 is greater than the area of the opening 23 through the piston 14 so as to retain the necessary volume of fluid back of the piston to operate the same as aforesaid. The capacity of the opening 23 can, of course, be manually regulated by the needle valve 24 or automatically controlled by the spring pressed check valve 24A shown in Figure 9 when, for example, driving machine screws, sheet metal screws and the like wherein their torsional resistance varies from maximum at the start to minimum after the threads are cut and then to maximum when finally driven home. Since the chuck 18, the hollow shaft 20, and the pump 8 are united into a single unit, a constant torque will be applied to the driver bit during any rotation of the main housing to thereby maintain what might be termed follow through forces to the impact of the teeth of the piston against those of the chuck. Thus the driving forces are divided beween impact and fluid pressure.

In the modification shown in Figure 7 the tool chuck end of the main housing 1A is permanently closed by an end wall 5A through which the tool chuck 18A rotatably extends. The interior of the housing is formed with an annular shoulder 30. A pump housing 31, instead of being formed integral with the main housing 1 as in Figure 1, is removably secured within the main housing by the disc 26A and plug 4A. Since the pump 8A is secured by its hollow shaft 20A to the tool chuck 18A theentire internal-assembly can be conveniently withdrawn by merely removing the plug 4A.

As best shown in Figure 8 I prefer at the present time to form the teeth 14 and 15 on the piston and chuck, respectively, on complementary angles. of 11 8,degre.es,-;.but, of course,;do:not;wish. to be '1imitediin.this respec.t;

klnsgFigure 9 I show ;the :opehingZSAin .the;.piston 14A provided-awith .a :regulatable .spling llrged .balll check valve 24A instead'of theneedlevalvei24 shown in Figure. 1.

lnqboth; forms :of; theinventiorr the; :plugs .4. and ;4A .are provided :with-;a guide1pin.:32for insertion through an aperture in theldisc'26 andinto. an opening 33 formed in the pump housingfor.conyenientlylocating the opening.27 -With1the hollowshaft andthe. .opening;28;with the interior .oithe pump housing. i

While I have..shown;:parti cular forms of embodiment .of 1 my invention .1 am :aware athat. man'y. minor changes therein readily .suggest themselves to -other. skilled, in ltheial't withoutdepartingfrom the spirit and scope ofthe .invenion. :Haying thus :described my invention what I .claimjas .newand'desire toiprotect by Letters Patent is:

11. A.:device jofithe tclass'. described comprising .a. fluid filledmain housingclosed. at bothofits ends and adapted for; attachment to :a .power. .tool "for rotation therewith, a .oolchuckextending through one. end' of the main .housing, the'opposite closed end of the main housing being bored inwardlytoprovidelarcylindrical pump housing, Ea :rotary pump :operatively disposed within .thepump housing and securedlto said tool c'huckby a hollow shaft, .a piston slidably mounted within the main .housing between the pumpand thetoolchuck andengaged with the main :housing for rotation therewith,.said pump. being in open communication withthe inside of the main housing .on one side of'the piston and through an. opening through the 'piston w'ith the. interior or .the main .housing .on the oppo- :site: side of the. piston, means formed .on the piston for engagement with 'means formed onthetool. chuckfor .a .tool chuck extending through one end of the main hous- -ing,..the.opposite. closed end of the main housing being bored-inwardly to provide a cylindrical pump housing,

a rotary pump operatively disposed within the pump housing and secured to said tool chuck by a hollow shaft, a piston slidably mounted within the main housing and on the hollow shaft between the tool chuck and the pump and slidably engaged with the main housing for rotation therewith, the inner end of the pump housing being in communication with the interior of the main housing on one side of the piston for directing fluid under pressure thereagainst and through a restricted opening through the piston with the interiorpf the housing on the opposite side of the piston and through said hollow shaft to the outer end of the pump housing,; ,a ndcooperating clutch elements formed on the piston and on the tool chuck for engagement with each other upon movement of the piston under fluid pressure from thepumpupon rotatiop of the main housing with respect to the pump for imparting rotation to the tool chuck.

3. A device of the class described comprising an elone y n rica .:fl id.filledrmainthous n lo e z -b of its ends and adapted for attachment to a power tool f r rotation th rewitha to l c c x n ns hr n onezcndofal h main. housin a.'yl .nd p m 9 92 remova ly secur drwi i t opp s n 'o t hO lSlIIg, a; rotarygpump disposed within the pump housing andoperableby;rotation of the main housing, said rot y.- pnmp being c re to t o h k y, a ho l shaft, apistomslidablymountedwithin the main housing on.th ihqll w haftb w e h tool .c us an the Pump and slidably engaged with the pump housing forrotation t r wit ;.-th innc en .QfIh pump h ns ei s ifi onnn nica mnwithth inte o 9 t m h in 95 one,side-of said piston for directing fluid pressure thereagainst and through a. regulatab le opening through the piston with the interior of the housing on the opposite side;.ot the -pistontand. through said hollow shaft: tothe u en p he pump ousin i n .cqo a 1 mb elements formed on the piston and .on the tool chuck for V engagement with each other upon-movement of thepiston .under fluid; pressure from the pump upon rotation of the main housing with respect to the pump for imparting'rotation to the-tool chuck.

References. Cited in the file of this patent UNITED STATES PATENTS 2,719,621 'Clough Oct. 4, 1955 

